Surfaces which have been paved with asphalt, concrete or other material typically develop cracks. These cracks can be due to the expansion and contraction of joints, the freezing and thawing of water that has worked its way into the pavement, the movement of the ground underneath or simply excessive impact. Such cracks cause problems because they degrade the pavement resulting in an uneven surface and loose debris.
Various methods have been employed to remedy the problems caused by such cracks. Repaving the surface is one option, but this is not always practical. A preferred method, is to seal the cracks by filling them with a flowable material which hardens over time while retaining a degree of flexibility.
Moreover, when sidewalks, runways and other roadways are initially fabricated, they are typically laid out in sections with expansion joints between adjacent sections to accommodate expansion and contraction due to atmospheric changes. Frequently, such expansion joints are comprised of the same material used to seal cracks.
A common technique for filling expansion joints or cracks is dispensing flowable material from a pouring pot (a device resembling a watering can) by manually tilting the pot. This technique has a number of significant disadvantages. First, the flowable material is usually heated in excess of 200.degree. F. to allow it to achieve a liquid state, thus, the person using the pouring pot must protect against burns. Second, since the pot has no heat source, the material must be poured quickly or it will solidify. This is especially true in colder weather. User fatigue and human inaccuracy are also factors which contribute to poor end results and are a direct result of using the pouring pot technique. (As regards inaccuracy, it is important to note that accurate placement of the sealant material in the crack or expansion joint is critical on an airport runway. This is because as airplanes take-off and land, the wheels get so hot, they can pull the sealant material right off the runway. If this happens, pieces of the material can be drawn into a jet engine and disable it. Thus, there are rigid FAA specifications which must be adhered to in the application of the sealant on airport runways.)
One attempt to overcome the disadvantages associated with the pouring pot technique, is an apparatus which includes a long wand, connected by a feeder hose to a large, mobile heated kettle (see U.S. Pat. No. 4,620,645). However, this approach also has several drawbacks. First, the wand is attached to the large kettle (usually part of or pulled by a truck) which limits the operator's range of movement to an area determined by the length of the feeder hose. Thus, at least two people must be on a single site to keep the project from being continuously interrupted. Additionally, the wand itself is very heavy and hot and is carried by the user. Fatigue therefore becomes a significant factor.
A number of other devices have been developed. These devices are essentially mobile hand carts, many of which include heated holding vessels, pour spouts and fuel storage tanks. ( See e.g. U.S. Pat. Nos. 2,578,080, 3,227,055, 3,280,710, 3,873,227, 4,732,109, 4,831,958 and Aeroil Municipal and Road Maintenance Equipment Catalog No. 1-89, page 14.) These devices, while providing some improvement suffer from still other problems. First, all include burner elements, and the manual ignition of fuel at the burners entails the risk of injury from explosion. For instance, Aeroil's suggested ignition procedure is to light a piece of paper, start the fuel flowing to the burner and then to roll the cart over the lit paper. Still further, if the wind blows out the flame or the flow of fuel is momentarily interrupted thereby extinguishing the flame, there is nothing to prevent the build-up of unconsumed fuel near the burners. This clearly imposes the risk of injury. The inability to adequately clean these devices is another serious drawback. For instance, the round shape of the Aeroil holding vessel severely limits the ability to scrape out debris and solidified material. Still further, the parts of most of the aforementioned devices are permanently welded or fastened together such that the pour spouts and other components cannot be repaired or replaced as necessary.
The provision of a method and apparatus which affords a way of effectively, safely and conveniently dispensing a flowable material suitable for the filling and sealing of cracks or joints, as aforementioned, would be a substantial advance.